Galba truncatula: Distribution, Presence in Fountains and Identification of Factors Related to Its Occurrence in Bulgaria

<i>Galba truncatula</i> acts as an intermediate host for several parasitic flukes of veterinary importance, but a targeted study on its spatial presence as well as the impact of environmental factors in Southeastern Europe has not been conducted. During the summer months of 2017 and 2018, a survey of 191 water bodies in 14 districts in Central, Southern and Western Bulgaria was conducted, with a focus on animal drinking fountains. Each site was assessed for snail presence and characterized by altitude, temperature, precipitation, shade and type of water body. Logistic regression modeling was used to identify the important factors related to the occurrence of snail species. The frequency of habitats found was 29.3%, with no differences observed between the studied districts (<i>p</i> > 0.05). Snails were present across a wide range of altitudes (78-1926 m), annual mean temperature (7.8-14.0 °C) and annual mean precipitation (523-796 mm). The high habitat frequencies were recorded in streams (60.0%) and on the banks on small rivers (50.0%). The presence of snails in the two studied types of fountains (without or with a concrete platform) was 24.1% and 17.2%, respectively, with no significant difference between them (<i>p</i> > 0.05). Regression analysis revealed temperature, shade, and type of water body as factors that could significantly influence the spatial presence of <i>G. truncatula</i>. The findings demonstrate the ecological adaptability of <i>G. truncatula</i> and highlight its presence in habitats with high potential for contact with domestic and wild ruminants. This information fills a regional knowledge gap and can support risk assessment and control measures for fluke-borne diseases in livestock and wildlife.